Ignition Source System for an Exothermic Reaction Mold Device

ABSTRACT

An ignition source system for an exothermic reaction mold device for welding conductors. The system includes a crucible in a block with an open top so that the crucible receives an exothermic weld material. The conductors to be welded exothermically are placed in the weld cavity of the mold. A lid covers the open top wherein the lid has an opening therethrough. An electronic thermal igniter assembly has an ignition component receivable through the opening in the lid so that the exothermic weld material may be ignited by the electronic thermal igniter assembly. The igniter plug rests on top of the lid and the ignition body is retained in a recess within the igniter plug.

REFERENCE TO PENDING APPLICATION

This application is a continuation application based on U.S. patentapplication Ser. No. 12/843,377, filed Jul. 26, 2011 entitled “IgnitionSource System for an Exothermic Reaction Mold Device”, which is based oncontinuation-in-part of U.S. patent application Ser. No. 12/632,417filed Dec. 7, 2009, now U.S. Pat. No. 7,946,466 entitled “AlternativeIgnition Source System for an Exothermic Reaction Mold Device”.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an alternative ignition source systemfor an exothermic reaction weld mold device. In particular, the presentinvention is directed to an exothermic reaction weld mold device whereinalternate sources of ignition may be chosen and utilized for initiatingan exothermic reaction for joining connectors.

2. Prior Art

The use of exothermic reaction welding is known for joining connectorsto each other and also for joining other metal parts, such as groundrods.

A reusable mold contains an internal crucible in which an exothermicweld metal is placed. When the exothermic weld metal is ignited, anexothermic reaction results in the crucible. The weld metal liquefiesand the molten material flows into a weld cavity in the mold.

The exothermic reaction process is initiated by an ignition which mayoccur from various sources. A spark or ignition gun, sometimes referredto as a flint ignitor, is often used to start the exothermic reactionwhich takes place extremely quickly once ignited. One example of a moldignited by a flint ignitor is shown in Assignee's U.S. Pat. No.6,776,386 entitled LID FOR EXOTHERMIC REACTION WELDING MOLD.

Alternatively, an electric ignition element having high resistance maybe used to start the exothermic weld reaction. An electrical ignitionsystem is advantageous in some cases since it may be initiated from agreater distance away from the mold itself.

Examples of prior exothermic molds that incorporate electrical ignitioninclude Brosnan et al. (U.S. Pat. No. 4,889,324) which discloseexothermic welding with an ignition system having a pair of leads toconnect to an ignition fuse or hot wire.

Another example is shown in Harger et al. (U.S. Pat. No. 6,994,244)which discloses an exothermic welding assembly including an electricaligniter which is embedded in the exothermic weld material.

Assignee's U.S. Pat. No. 7,240,717 discloses an electrical ignitionsource including an igniter element suspended above the lid of the molddevice outside of the crucible.

The exothermic reaction weld is often times made in the field in remotelocations and in all types of conditions. Accordingly, it is desirableto have a choice of ignition sources. Additionally, the weld may be madein confined spaces, such as an open trench, wherein a ground wire isbeing installed or a cable is being joined.

If electrical ignition tools are not present at the site, it would bedesirable to have an alternate source to ignite the exothermic weldreaction. Alternatively, if spark ignition materials are not availableat the site, it would be desirable to have an alternate source toinitiate the exothermic reaction welding.

Accordingly, it is a principal object and purpose of the presentinvention to provide an alternate source exothermic reaction weld molddevice.

It is a further object and purpose of the present invention to providean exothermic reaction weld device that will accommodate various typesof ignition systems.

It is a further object and purpose of the present invention to providean ignition source system that may be used with a wide variety ofexisting molds and mold designs.

It is a further object and purpose of the present invention to providean electronic thermal igniter assembly having an ignition bodyreceivable through an opening in a lid of a mold wherein the ignitionbody is retained in an igniter plug.

SUMMARY OF THE INVENTION

The present invention is directed to an alternative ignition sourcesystem for an exothermic reaction mold device.

Exothermic welding is used for joining conductors mainly copper tocopper, or copper to steel surfaces. The exothermic reaction takes placein a mold which is often made up of a graphite block and is able towithstand high exothermic temperature. A crucible which is the mostimportant part of the mold is where the exothermic reaction takes place.A steel metal disk is placed in the crucible followed by the weld metalwhich is often a mixture of copper oxide and aluminum. Traditionally,starting powder is placed on top of the lid and the reaction is ignitedusing a flint ignitor. The weld metal is a mixture of copper oxide andaluminum which produces copper and aluminum oxide after an exothermicreaction takes place.

The present invention includes a mold block and two alternate sources ofignition—an electronic thermal igniter assembly and a mechanicallygenerated spark igniter.

The mold block also includes a mold cavity below the crucible which willreceive molten material flowing from the exothermic reaction takingplace in the crucible through a passageway.

A lid covers the open top of the mold block. The present invention maybe utilized with lids of various types. In one preferred embodiment, thelid includes an upper top face with a cylindrical opening extendingthrough the lid. The lid also includes a bottom or lower face opposed tothe upper or top face. The bottom face includes an opening therethrough.An exhaust vent between the upper face and lower face of the lid forms apocket in communication with the cylindrical opening and opening of thebottom face. The exhaust vent is vented through the side face of thelid.

In one of the alternate sources of ignition, the electronic thermaligniter assembly includes an extending ignition body which is receivableinto and through the cylindrical opening in the lid and extends into thecrucible until it is just above the level of exothermic weld material.The ignition body is retained in a recess in an igniter plug. Theigniter plug contains a high temperature plastic hollow enclosure withflat metal spring contacts housed within. The metal spring contacts willtightly hold the ignition body in place in order to form a closedcircuit. When installed, the igniter plug will rest against the top ofthe lid and close the opening in the lid when the ignition body isreceived therethrough. The ignition body and the igniter plug are, inturn, wired to a power source and a switch or switches.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of alternative ignition sourcesystem for an exothermic reaction mold device constructed in accordancewith the present invention;

FIG. 2 illustrates a mold block of the present invention as shown inFIG. 1;

FIG. 3 shows a top view of the invention shown in FIG. 1 utilizing anelectronic thermal igniter assembly as an ignition source;

FIG. 4 illustrates a side view of the invention shown in FIG. 3;

FIG. 5 illustrates a sectional view taken along line 5-5 of FIG. 3;

FIG. 6 illustrates a sectional view taken along line 6-6 of FIG. 3; and

FIG. 7 illustrates a completed weld performed by use of the presentinvention.

FIG. 8 illustrates an exploded perspective view of an igniter plug ofthe electronic thermal igniter assembly; and

FIG. 9 illustrates a perspective view of the igniter plug shown in FIG.8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments discussed herein are merely illustrative of specificmanners in which to make and use the invention and are not to beinterpreted as limiting the scope of the instant invention.

While the invention has been described with a certain degree ofparticularity, it is to be noted that many modifications may be made inthe details of the invention's construction and the arrangement of itscomponents without departing from the spirit and scope of thisdisclosure. It is understood that the invention is not limited to theembodiments set forth herein for purposes of exemplification.

Referring to the drawings in detail, FIG. 1 illustrates a perspectiveview of an alternative ignition source system for an exothermic reactionmold device 10 construction in accordance with the present invention.

The invention includes a mold block 12 and may permit two alternateforms of ignition—an electronic thermal igniter assembly and amechanically generated spark igniter.

FIG. 2 illustrates a perspective view of the mold block 12 apart fromthe other components with the mold block opened for ease of viewing. Themold block which may be reused multiple times, and may be composed ofgraphite, ceramic or other refractory material.

Exothermic welding is used for joining conductors mainly copper tocopper, or copper to steel surfaces. The exothermic reaction takes placein a mold which is made up of a graphite block and is able to withstandhigh exothermic temperature. A crucible which is the most important partof the mold is were the exothermic reaction takes place. A steel metaldisk is placed in the crucible followed by the weld metal which is amixture of copper oxide and aluminum. Traditionally, starting powder isplaced on top of the lid and the reaction is ignited using a flintignitor. The weld metal is a mixture of copper oxide and aluminum whichproduces copper and aluminum oxide after an exothermic reaction takesplace.

The present invention provides for alternative sources of ignition ofthe exothermic weld reaction. FIGS. 3 through 6 along with FIGS. 8 and 9illustrate the use of the electronic thermal igniter assembly as anignition source.

One type of mold block 12 is illustrated in the present embodimentalthough it will be understood that a wide variety of molds may be usedwithin the teachings of the present invention. A first portion 20 of themold device 12 joins with a second portion 22 of the mold device 12.When the portions 20 and 22 are joined together as shown in FIG. 1, acrucible 24 is formed having an open top 26 as seen in FIG. 2.

The base of the crucible 24 has a shoulder 28 to receive a small metaldisk 18 such as a steel metal disk (not shown in FIG. 2).

Clamps 30 retain the mold portions 20 and 22 so that they may movebetween a closed position shown in FIG. 1 and an open position shown inFIG. 2. Handles 32 extending from the clamps 30 may be utilized to movethe clamps 30 and, in turn, move the mold portions.

The mold block 12 also includes a mold cavity 34 below the crucible 24which will receive molten material flowing from the exothermic reactiontaking place in the crucible 24 through a passageway 36.

A lid 40 covers the open top 26 of the mold block 12. The lid 40 may beconnected by a hinge or hinges to the mold block 12. It will beunderstood that the present invention may be used with lids of varioustypes. In one preferred embodiment, the lid 40 includes an upper or topface with a cylindrical opening 38 extending through the lid 40. The lidalso includes a bottom or lower face opposed to the upper or top face.In the present embodiment, the upper top face is parallel to the bottomface. The bottom or lower face includes an opening 42 therethrough. Theopening 42 may be elliptical oval, or take other shapes. The cylindricalopening 38 has an axis perpendicular to both the top and the bottomfaces and passes through the opening 42. Between the top face and thebottom face of the lid 40 are a series of side faces including a sideface 44. An exhaust vent 46 between the upper face and the lower face ofthe lid forms a pocket in communication with the cylindrical opening 38and the opening 42 of the bottom face. The exhaust vent 46 is ventedthrough the side face 44 of the lid 40.

The cylindrical opening 38 also includes a counter sunk receptacle 48 inthe top face which is used to retain a portion of starting powder whenutilizing the mechanically generated spark igniter as an ignitionsource.

The present invention employs alternative ignition sources in order toinitiate an exothermic reaction. A first ignition source is a remotelyactivated electronic thermal igniter assembly while a second, alternateignition source is a mechanically generated spark. FIG. 3 shows a topview, FIG. 4 illustrates a side view, FIG. 5 illustrates a sectionalview and FIG. 6 illustrates a sectional view of the invention with theelectronic thermal igniter assembly employed. FIGS. 8 and 9 show anexploded perspective and perspective view of the igniter plug to createthe ignition spark within the electronic thermal igniter assembly,respectively.

The electronic thermal igniter assembly includes an extending fiat bladeignition body 50 which may be seen apart from the mold block 12 inFIG. 1. The ignition body 50 includes a strip or wire of two differentmetallic elements in contact with each other. In one non-limitingexample, the metallic elements are palladium and aluminum. When anelectrical charge is applied, the elements will alloy. The electronicignition body 50 is receivable into and through the cylindrical openingin the lid 40. When installed, the ignition body 50 extends into thecrucible 24 until it is just above the level of exothermic weld material52, as best seen in FIGS. 5 and 6.

The ignition body 50 is not and should not be in contact with theexothermic weld material as the ignition body works more effectivelywhen suspended above the weld metal. When ignition is initiated, thesparks generated from the ignition body broadcast more evenly over theweld material producing a more consistent and even reaction of the weldmaterial.

The ignition body 50 is inserted into a recess in the igniter plug 54and is replaceable each time an exothermic reaction is desired. Theignition body 50 is retained in a recess in an igniter plug 54. Theigniter plug 54 is an embodiment built of high temperature material thatcontains two outer components, 72 and 74, as can be seen in FIG. 8. Thetwo outer components 72 and 74 are preferably designed of hightemperature plastic to sustain the extreme heat that the ignition emits.The two outer components 72 and 74 are assembled together and securedwith a screw 76 and nut 78 to form a hollow housing around the springcontact mechanism, as shown in FIGS. 8 and 9. The outer shell could bedesigned to be secured with a heat resistant latch to tightly enclosethe housing. The housing needs to be hollow to create a void space forthe spring contact mechanism, 80 and 82, to latch into place. The outercomponents 72 and 74 could also be formed of graphite or some other typeof metal. Also, the igniter plug 54 is a very robust unit that is meantto be used multiple times before being replaced out in the field.

Unlike past designs that contain twisted copper wires as a pair ofconductors, the spring contact mechanism consists of two fiat metal bodyigniter contacts, 80 and 82, as shown in FIGS. 5 and 8. The ignitercontacts 80 and 82 are made of metal so they act as a pair of conductorsfor the electrical current to run through the ignition body 50. Thespring contact mechanism 80 and 82 resides within either side of the twohousing components 72 and 74, as shown in FIG. 8. The inner part of thehousing components 72 and 74 contain a custom fit in the shape of thespring contacts with two shoulders so that spring contacts 80 and 82 canproperly fit within the housing unit. The spring contacts 80 and 82 forma confined spacing between each other that is smaller than the distanceof the width of the ignition body 50. This forms a friction-lessreceptacle for the ignition body 50 to be retained in a recess, as shownin FIG. 5.

Each open end of the igniter contacts 80 and 82 is connected via thelead wire 56, which have been soldered and crimped onto each springcontact, to a voltmeter assembly in the remote unit 58, as shown in FIG.5. Ignition body 50 enters the spring contacts 80 and 82 through thespacing between the closed ends, as shown in FIG. 5. The closed ends atthe bottom of the spring contacts 80 and 82 form the clamp to hold theignition body 50 tightly in place. In order to prevent an accidentalmelt of the fuse from the voltmeter assembly, the closed ends of theigniter contacts 80 and 82 do not touch each other. This accidental meltcould occur if the operate button is pushed without the presence of theigniter body 50, creating a high safety risk. The ignition body 50 fitstightly in between the spring contacts in order to form a complete,closed circuit, as shown in FIG. 5.

The igniter body 50 includes a printed circuit board insulated on allsides with an ignition component 64 in the form of a metallic wiresoldered to the board to complete the circuit. The ignition component 64spans an opening in the ignition body 50 and may be configured as astraight wire, as a loop or another configuration.

Once installed, the igniter plug 54 will rest against the top of the lid40 and substantially closes the central opening in the lid 40 when theignition body 50 is received therethrough. The flat base of the igniterplug 54 enables it to rest against the top of lid 40. This flat base isimportant because it provides adequate protection from the exothermicreaction and sparks generated within the ignition source system. Theflat base of igniter plug 54 substantially covers the opening in the lidand acts as a seal, as shown in FIG. 5.

The igniter contacts 80 and 82 within the igniter plug 54 are connectedvia the lead wire 56, through the opening 84 within the external housingunit, to a battery or multiple batteries or to another power source 58and a switch or switches 60, as shown in FIG. 5. The lead wire 56 issurrounded by thick insulation, thus providing an adequate seal withinthe opening 84 in the ignition plug 54. The lead wire 56 from theignition plug 50 to the remote unit 58 has the option of being replacedout in the field, thus making it easier for the user to manually fix theassembly. In one non-limiting configuration, an arming and an operationswitch may be employed. An optional battery life voltage sensingindicator 60 with a voltage sensing circuit may be included. Theignition plug 54 may be easily assembled and disassembled formaintenance, inspection, or repair.

The replaceable ignition body 50 is designed so that the same sizecomponent is used for the smallest weld shot to the largest weld shot.

The batteries 58 may be standard replacement alkaline batteries and maybe contained in a housing with the switch or switches 60 in a portable,handheld device so that the exothermic reaction is initiated remotelyfrom the mold device 12.

In order to utilize the present invention, a cable, cables or othercomponents to be welded are positioned in the mold cavity 34 and a metaldisk 18 is inserted into the crucible 24. Exothermic weld material 52 isplaced in the crucible and, optionally, a portion of starting powder issprinkled on top of the exothermic reaction material. Thereafter, thelid 40 is closed covering the open top. The ignition body 50 is theninserted through the cylindrical opening 38 of the lid until the igniterbody rest against the top of the lid 40. Once the switch or switches 60are activated, electricity is delivered through the wires to a printedcircuit board in the igniter body and to the ignition body 50. In oneembodiment, a first arming switch and a second ignition switch are used.The ignition body 50 will generate heat causing sparks or discreetparticles to fall onto the exothermic weld material and/or startingpowder causing the weld material 52 to turn into molten liquid material.The igniter plug 54 blocks escaping gases from venting out of the top ofthe lid. The metal disk 18 will be melted, causing the molten materialto flow through the passageway 36 into the mold cavity 34 forming anelectrical connector in the cavity.

Use of the electronic thermal igniter assembly provides an easy and safemethod of initiating an exothermic weld.

As an alternate ignition source, a mechanical spark may be utilized.Once again, the connector or connectors are inserted into the moldcavity 34, a metal disk 18 is placed in the mold block 12 and exothermicweld material 15 is inserted into the crucible in the block. Thereafter,the lid 40 is closed. A portion of starting powder is placed in thecounter sunk receptacle in the top of the lid 40. A spark may bemechanically generated by use of a flint ignitor brought near thestarting powder. The starting powder will initially be ignited whichwill cause sparks to pass through the cylindrical opening 38 into thecrucible which will cause the exothermic weld material to be reduced.The metal disk 18 will be melted, causing the molten material to flowthrough the passageway 36 into the mold cavity.

FIG. 7 illustrates a completed connector 70 formed by the presentinvention.

In the case of either of the ignition sources, the exhaust vent throughthe side of the lid 40 forms a vent for hot, escaping gases from theexothermic reaction.

Whereas, the present invention has been described in relation to thedrawings attached hereto, it should be understood that other and furthermodifications, apart from those shown or suggested herein, may be madewithin the spirit and scope of this invention.

1. An ignition source system for an exothermic reaction mold device,which system comprises: a crucible in a block with an open top so thatsaid crucible receives an exothermic weld material; a removable lidcovering said open top; an electronic thermal igniter assembly having anignition body, said ignition body extending into said crucible so thatsaid exothermic weld material may be ignited by said electronic thermaligniter assembly; and an igniter plug having a connector housing unitwith a spring contact mechanism for capturing said ignition body whereinsaid ignition body is retained in a recess of said igniter plug.
 2. Analternative ignition source system for an exothermic reaction molddevice, which comprises: a crucible in a block with an open top so thatsaid crucible receives exothermic weld material; a lid covering saidopen top wherein said lid has an opening therethrough; means to ignitesaid exothermic weld material within said crucible with an electronicthermal igniter assembly having an ignition body which extends into saidcrucible wherein said electronic thermal igniter assembly includes anigniter plug, at least one battery and at least one switch; and means toalternatively ignite said weld material within said crucible with amechanically generated spark.
 3. An alternative ignition source systemfor an exothermic reaction mold device as set forth in claim 2 whereinsaid ignition body is an insulated printed circuit board with an openingspanned by a metallic wire.
 4. An alternative ignition source system foran exothermic reaction mold device as set forth in claim 2 wherein saidblock is composed of graphite.
 5. An alternative ignition source systemfor an exothermic reaction mold device as set forth in claim 2 whereinsaid ignition body includes an insulated printed circuit board.
 6. Analternative ignition source system as set forth in claim 2 wherein saidmeans to ignite said weld material in said crucible with a mechanicallygenerated spark includes a flint igniter.
 7. An alternative ignitionsource system for an exothermic reaction mold device as set forth inclaim 2 wherein said ignition body is removably retained in said igniterplug.
 8. An alternative ignition source system for an exothermicreaction mold device as set forth in claim 2 including a battery lifevoltage sensing indicator wherein said at least one battery, said atleast one switch and said battery life voltage sensing indicator arecontained in a housing.